Daily Active Users (DAU)
Unique users who engage with your product in a single day.
What it measures
Count of unique users with at least one qualifying action in a 24-hour period. What counts as "active" is product-specific: it might be logging in, viewing content, or completing a core action.
Calculation Variants
- Calendar Day (UTC)
- The industry standard for globally distributed apps. Resets at midnight UTC.
- Calendar Day (Local Time)
- Resets at midnight in the user's local timezone. Better for measuring daily habits (e.g., morning routines), but harder to aggregate.
- Rolling 24-Hour
- Count of unique users in the trailing 24 hours. Used strictly for real-time operational dashboards.
What to watch
- Rising: Indicates growing engagement, but verify sustainability. A viral spike that fades within 7-14 days signals temporary interest, not real growth. Pair with retention metrics.
- Falling: Could signal product issues, seasonality, or a shift in user behavior. Segment by cohort to identify whether it's new user acquisition or existing user engagement that's declining.
In practice
After launching push notifications, a productivity app saw DAU jump 40% in week one. But sessions per user dropped from 3.2 to 1.8. Users opened the app more but did less each time. The team shifted to weekly digest notifications, which recovered session depth while maintaining the DAU gain.
Illustrative scenario — a representative composite, not a specific company.
Vanity Risk
Without retention context, DAU is a vanity metric. A viral spike that fades within two weeks signals temporary interest, not real growth. Always pair with retention curves.
Related: Retention — viral spikes mean nothing without retention.